Recent advances in electronic technology which have made available low cost but efficient microprocessor systems have led to the development of improved electronic measuring systems capable of providing a digital indication representative of a value to be measured. These microprocessor controlled systems, such as that disclosed by U.S. Pat. No. 3,962,570 to Loshbough, provide automatic zeroing, zero set functions, tare control, and many other functions previously provided by much more complex logic circuits, such as that disclosed by U.S. Pat. No. 3,665,169 to Henderson et al. Additionally, microprocessor measuring systems may be programmed to provide a number of calibration functions and other program control functions which previously have been performed by excessively expensive, large and complex electronic units.
Although microprocessor technology has resulted in the development of electronic measuring systems having greatly enhanced capabilities, such systems are generally still of substantial size, expensive, and difficult to service. This is particularly true when the measuring system is combined with both a visual digital indicator and a printer assembly for providing a record printout of the visual display. Combined electronic measuring and printer systems, such as those used for electronic weighing, are generally both large and complex, as illustrated by U.S. Pat. Nos. 3,623,119, to Orr and 3,701,991 to Livesey. Consequently, there is a demand for a small, compact, modular electronic measuring unit and printer system which may be operated from either a battery or a conventional power supply and which, although adapted to a wide variety of uses, may be easily and inexpensively serviced and repaired.